PHP4.3.0-Configure crashes with option --with-gd

[tammo]

Hi I got a real big Problem

When I install php 4.3.0 with --with-gd option the configure crashes "checking for floorf... no
If configure fails try --with-jpeg-dir=<DIR>
configure: error: libpng.(a|so) not found.
"

I don't no what to do. I already pointed to the bundeled gd directory in php-4.3.0/ext/gd with flag "-with-gd-dir"

Please help me, its really urgent.

Thx